Keysight M9383B Measurement Manual page 70

5G New Radio (NR) Measurements using X-Apps
5G Waveform, EVM, and ACP Analysis Using X-Applications
Once you have achieved optimum EVM, a change in the VXG power level will
TIP
work in parallel with mechanical attenuation to maintain optimum EVM. For
example, if the VXG power level was set to 5 dBm and the mechanical
attenuation was set to 14 dB, a 2 dB increase to the VXG power level (7 dBm)
will result in a 2 dB increase to the mechanical attenuation (14 dB to 16 dB).
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Similar to adjusting the attenuation level, increase the IF Gain one step at
a time while monitoring the EVM. When an increase to the IF Gain worsens
the EVM, back off one increment.
For this example, the optimum EVM was achieved with Attenuation set to
14 dB and IF gain at 2 dB.
M9383B/84B Measurement Guide